With the advent of the Internet age, people can use electronic devices to communicate and interact with each other at any time and in any place through wireless networks. In addition, a microphone for making a call or receiving commands has gradually become one of the essential components of the electronic device such as a smart watch, a notebook computer, a tablet computer, a personal digital assistant, a smart phone or a game console.
Generally, a microphone comprises plural sound-receiving parts. After the microphone is produced, it is necessary to test the sound-receiving functions of the sound-receiving parts. Please refer to FIGS. 1A and 1B. FIG. 1A schematically illustrates the architecture of a conventional microphone test device. FIG. 1B schematically illustrates the appearance of the conventional microphone test device. As shown in FIG. 1A, the microphone test system 9 comprises a computing device 90 and an anechoic box B. A test program 91 is executed in the computing device 90. The computing device 90 comprises a sound card 92, a microphone pre-amplifier 93, a connection interface 94 and a power amplifier 95. The sound card 92 is electrically connected with the power amplifier 95. The test program 91 is executed to connect and control the sound card 92, the microphone pre-amplifier 93 and the connection interface 94. For example, the connection interface 94 is a digital connection interface or an analog connection interface. Moreover, three standard speakers 96, three standard microphones 97 and an under-test microphone 8 are disposed within the anechoic box B. The anechoic box B is capable of isolating the interference of the ambient noise. Consequently, the accuracy of testing the under-test microphone 8 can be increased. The standard speakers 96 are electrically connected with the power amplifier 95. The standard microphones 97 are electrically connected with the microphone pre-amplifier 93. The under-test microphone 8 is electrically connected with the connection interface 94. In case that the under-test microphone 8 is a digital microphone, the connection interface 94 is a digital connection interface. In case that the under-test microphone 8 is an analog microphone, the connection interface 94 is an analog connection interface.
Please refer to FIGS. 1A and 1B again. The under-test microphone 8 comprises a first sound-receiving part 81, a second sound-receiving part 82 and a third sound-receiving part 83. Each sound-receiving part is aligned with the corresponding standard speaker 96 and the corresponding standard microphone 97. During the process of testing the under-test microphone 8, the test program 91 controls the sound card 92 to drive the power amplifier 95. Consequently, each of the standard speakers 96 generates a test acoustic wave S. The test acoustic wave S is transferred to the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83. At the same time, the scattered test acoustic wave S is received by the standard microphones 97, which are arranged beside the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83. After the test acoustic wave S is received by the first sound-receiving part 81, the second sound-receiving part 82, the third sound-receiving part 83 and the standard microphones 97, the corresponding sound signals are transferred from the under-test microphone 8 to the test program 91 through the connection interface 94 and transferred from the standard microphones 97 to the test program 91 through the microphone pre-amplifier 93. Consequently, the sound signals are further tested and analyzed.
Please refer to FIG. 1C. FIG. 1C is a frequency response diagram illustrating the testing result of the conventional microphone test system. In FIG. 1C, the X axis denotes the frequency (unit: Hz) of the sound signal received by the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83, and the Y axis denotes the intensity (unit: dB) of the sound signals received by the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83. The positions of the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83 of the under-test microphone 8 are different. Consequently, when the test acoustic wave S transferred to the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83, different acoustic wave reflection phenomena are generated. The reflected sound signals may influence the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83 on reception of the test acoustic wave S. Consequently, the frequency response curves of the first sound-receiving part 81, the second sound-receiving part 82 and the third sound-receiving part 83 in the low frequency band (e.g., 100 Hz˜200 Hz) and in the high frequency band (e.g., over 2000 Hz) are not well consistent with each other. Under this circumstance, the microphone test system 9 cannot accurately test whether the sound-receiving function of the under-test microphone 8 in the low frequency band and in the high frequency band is normal or not.
Therefore, there is a need of providing a microphone test device capable of achieving more consistent frequency response curves in the low frequency band and in the high frequency band so as to increase the accuracy of testing the sound-receiving function of the under-test microphone in the low frequency band and in the high frequency band.